The official inquiry into the blaze last August at the Aldermaston Atomic Weapons Establishment (Awe) by the Royal Berkshire fire and rescue service contains strong criticism of the nuclear plant's firefighting performance. There were "numerous problems" with the way the emergency was tackled, the report said. Aldermaston's on-duty emergency controller was "overwhelmed by the demands of the incident and unable to effectively provide the information required".

The fire started just after 9pm on 3 August when a solvent used in making explosives, methyl ethyl ketone, burst into flames. It burned for nearly nine hours overnight in a building within Aldermaston's explosives technology facility and it took 16 fire appliances and 68 firefighters to put it out.

The government's Health and Safety Executive is investigating whether to take legal action against Aldermaston. The results of the site's inquiry into the incident are due to be published in the next few weeks.

Berkshire fire service's "incident debrief" has been released in response to a request under freedom of information law. It said fire controllers discovered explosives were involved when they overheard a message in the background while they were on the phone.

Initial communications with Aldermaston were "limited", the report said. Communications with Ministry of Defence police were at times "poor", causing delays of more than an hour in some fire crews accessing the site.

Firefighters discovered that Aldermaston's hydrants, which are meant to be a vital part of the site's protection against fire, were so inefficient they had to bring in a special high-volume pump from London. The report blamed "a mistake with the opening and closing of sluice valves by a maintenance contractor".

There were "breaches of safety measures", including a premature attempt to reduce a safety cordon, a failure to distribute enough radiation badges causing delays, and fire and ambulance crews being left without security escorts.

The report pointed out that there were "numerous difficulties" with the agencies involved because the fire occurred at night and Aldermaston had strict security procedures. Access to the site was sometimes "slow", fire crews had to be escorted, and hourly co-ordination meetings could include up to 40 people.

Peter Burt of the Nuclear Information Service in Reading, which obtained the fire service report, accused the site's private sector managers, Awe, of downplaying the seriousness of the fire. It was described by the chief executive at the time, Robin McGill, as "a relatively small fire" to which the response had been "swift and effective".

Burt pointed out that the fire service had mobilised a major response, which had been "complicated by the inadequate numbers of staff on site, over-zealous security, and Awe's failure to maintain fire hydrant systems". He said: "This report shows clearly that the brave firefighters who attended the blaze were let down by failures and shortcomings in Awe's own safety arrangements."

Awe insisted, however, that it took "prompt action" to deal with the fire according to standard procedures agreed with safety regulators and the emergency services. "We are committed to learning all available lessons from the incident," said a spokesman."The company commissioned an independently led investigation into the cause of the fire and we expect to report the findings to the Awe local liaison committee within the next few weeks as well as making them publicly available."

A spokesman for the Health and Safety Executive said: "The HSE investigation into the incident at Awe in August 2010 is still ongoing and any decision on possible enforcement action is yet to be made."

• The headline of this story was changed on 31 May 2011. It originally stated that firefighters had been criticised. In fact, a report from Royal Berkshire fire and rescue service had been critical of the Aldermaston nuclear plant.